When the cold weather hits in Minnesota and other northern tier states, we begin to apply layers of clothing. If it’s clean, the air spaces trap warmth next to the skin. That’s the same reason a birdbath gets so much traffic in winter: the feathered friend must keep his or her feathers clean because if they should get oily or matted their thermal factor disappears.If you don’t believe this, wear your down jacket in the rain until it gets soaked. All the thermal ability disappears. And if you wash it the wrong way, you may mat the down and remove the fluffiness. (Use a down-friendly detergent, and toss a couple of tennis balls in to keep the feathers from matting.)Layers, however, must be applied in the correct order, and pulled up or down over the previous layers.In the case of a male, at the bottom is the underwear shorts, followed by the t-shirt.Next in order of appearance are the socks (optional, now or later), then the long underwear bottom, followed by a long underwear top.Now, if you didn’t put your socks on before your long underwear bottoms, pull on warm socks and bring the ankle part up over the long underwear legs.Drag your shirt on and button it.Last, climb into your pants and tighten your belt over the bottom of the shirt.There, now you should be proof against the stray spare zephyr or other.